<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        samp{
            color: blue;
        }

    </style>

    <link href="demo.css" rel="stylesheet">
</head>
<body>

     <div style="color: blue">Hello css</div>

     <samp>Hello css</samp>

<p>hello css</p>
</body>
</html>